Electric compressor with integral inverter

ABSTRACT

An electric compressor provided with an integral inverter, incorporated with a motor and provided in a receiving space surrounded by a compressor housing with a motor drive circuit that includes the inverter. At least some of electric parts including the motor drive circuit are coated at an assembly-completed state with a resin that is charged into the receiving space. The shape of the charged resin is defined in the receiving space by a jig used at the time of resin charging and defining a space to be charged with the resin. In the structure of a resin coating section for such a motor drive circuit, the amount of resin charged is significantly reduced, and the entire compressor is reduced in weight and cost.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to an electric compressor with an integralinverter, incorporated in a compressor with a motor drive circuit thatincludes the inverter, and specifically relates to an electriccompressor with an integral inverter, which can minimize the chargingresin amount to insulate and protect the motor drive circuit, and whichcan be reduced as a whole in weight and cost.

BACKGROUND ART OF THE INVENTION

In a known structure of an electric compressor incorporated with a motordrive circuit including an inverter, etc., a motor drive circuit iscoated by a resin mold material for insulation so as to be buried in theresin mold material. (e.g. patent document 1)

Further, in another known structure, a power semiconductor modulelocated between a lid and a compressor housing (at the low pressure sidein the housing) is coated and buried by pouring a insulating syntheticresin, etc. which has been heated to be fluidized. (e.g. patent document2) In the structure described in patent document 2, a whole chambercontaining electric parts such as a power semiconductor module, etc. isfilled with a resin mold material.

Patent document 1: JP-2002-70743Patent document 2: JP-4-80554

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

However, in the above-described conventional structure, because themotor drive circuit, etc. are completely buried by charging with resinsubstantially all over the chamber containing the motor drive circuit,etc., the amount of the charged resin or resin usage increases, so thatit becomes difficult to reduce the cost and weight as a whole electriccompressor. And especially for an electric compressor used in an airconditioning system for vehicles, it is needed to reduce the cost andweight as far as possible.

According to such problems and needs in conventional electriccompressors, an object of the present invention is to provide anelectric compressor with an integral inverter incorporated with a motor,in which the charged resin amount for the structure of the resin coatedsection in the motor drive circuit, etc. can be greatly reduced to makea whole compressor reduced in cost and weight.

Means for Solving the Problems

To achieve the above-described object, an electric compressor with anintegral inverter according to the present invention is a compressorwhich is incorporated with a motor and provided in a receiving spacesurrounded by a compressor housing with a motor drive circuit thatincludes the inverter, characterized in that at least some of electricparts including the motor drive circuit are coated at anassembly-completed state with a resin that is charged into the receivingspace, and a shape of the charged resin is defined in the receivingspace by a jig used at the time of resin charging and defining a spaceto be charged with the resin.

In other words, in the above-described conventional structure the resinis charged substantially all over the chamber receiving the motor drivecircuit, etc., so that the resin is charged into a site which does nothave to be coated, such as an inner wall of the receiving chamber.However, in a structure of the present invention, the jig defining thespace to be charged with the resin is placed in the receiving space,during the charging with the resin into the receiving space. This jig isplaced for partitioning the space to be charged with the resin at a sitewhich needs to be coated with the resin, therefore does not basicallydefine the space to be charged with the resin at a site which does nothave to be coated with the resin. Therefore, as if an excess thicknessin a conventional resin-charged form was removed at a site which doesnot have to be coated with the resin, the amount of the charged resinand resin usage can be surely reduced so as to reduce in weight andcost. On the other hand, at a site which has to be coated with the resinthe resin can be surely coated at a predetermined thickness by chargingwith the resin into the space defined in a predetermined form to becharged with the resin.

As described above, the resin is charged at an assembly-completed statein the electric compressor with an integral inverter of the presentinvention. In a case that a lid member is provided to protect internalparts at the receiving space, the lid member may be dismounted to insertthe jig, and the lid member may be mounted again after the completion ofthe resin charging and the jig dismounting. It can be performedextremely easily to dismount the jig after the resin-chargingcompletion.

In the electric compressor with an integral inverter according to thepresent invention, such configuration can be employed that the jigdefines the space to be charged with the resin for at least some ofelectric parts including the motor drive circuit and does not define thespace to be charged with the resin for at least a part of the compressorhousing which defines the receiving space. Because many sites which donot require the resin coating exist in at least a part of the compressorhousing, specifically at an internal surface of the housing, whichdefines the receiving space. At such sites, the space to be charged withthe resin should be neither defined nor coated with the resin. Reductionin weight and cost are hereby achieved still more efficiently.

Further, it is possible that the jig, defines the space to be chargedwith the resin for at least some of electric parts including the motordrive circuit, and does not define the space to be charged with theresin for at least the other parts. When plurality of the electric partsare provided, there sometimes exists an electric part which does nothave either to be coated with the resin, or an electric part which doesnot have to be further coated with the resin at a site whose top sectionhas been already coated by its own coverings. In such a case, the resinshould not be coated at the sites which do not have to be coated, as faras possible. Whereby, further reduction of the amount of the resin usageand reduction in weight and cost can be achieved.

Further, the space to be charged with the resin may be defined so as toextend among at least some of electric parts. Whereby, specifically in aregion where the electric parts are closely located to each other atsmall distances in the receiving space, the resin-charging can beperformed integrally as straddling the electric parts. Therefore, eachelectric part can be fixed being kept in a predetermined form by thecharged resin, without damaging electrical connection, etc.

In the electric compressor with an integral inverter according to thepresent invention, it is preferable that at least some of electric partsincluding the motor drive circuit are provided in the receiving space soas to enable heat exchange with refrigerant sucked as fluid to becompressed. In other words, it is preferred that the motor drive circuitis provided in or near the compressor housing located at the refrigerantsuction path, so as to exchange the heat to the side of suckedrefrigerant. Employing such a structure, the inverter, liable to becomeoverheated can be properly cooled automatically, can maintain thedesignated performance of the motor drive circuit and can simplify thestructure because a cooling means is not required to be providedseparately.

In addition, it is preferable that the resin-charging is performed bycharging with a liquid resin material into the space to be charged withthe resin. Use of the liquid resin material can make the poured resinspread easily and quickly all over the appropriate region in the spaceto be charged with the resin, so as to simplify the work for theresin-charging. In a case that such a liquid resin material is used, theliquid resin material can be poured into the space to be charged withthe resin so as to coat the essential target site with the resin, in aprogression of the pouring process.

Further, it is also preferred in the present invention that at leastsome of electric parts including the motor drive circuit is charged withthe resin under a residual heat condition after heating. In such a case,because the resin material is well fluidized responding to the residualheat, this technique can be adopted when a sufficient charged resin isrequired even in a minimal space in the space to be charged with theresin.

Further, in the present invention, it is possible that the jig itself isformed so as to be heatable, such that the jig has a heat source. Insuch a structure, especially in a case that the charged resin is athermosetting resin, time to harden can be shortened by setting the jigtemperature at the cure temperature or above.

It is preferred that the resin material used for the resin to be chargedwith is a thermosetting resin such as urethane or epoxy, etc. Athermosetting resin, after properly hardened, can maintain asufficiently high heat resistance and durability even if the inverter,etc. becomes hot.

Further, a thickness of the charged resin (charged resin layer) ispreferably 1 mm or more. The charged resin with 1 mm or more thicknesscan ensure a desired insulation performance and protection performance.Though the upper thickness is not limited, it is preferable that thethickness is set less than about 8 mm, especially less than about 6 mm,because too large thickness may cause the same problem as conventionalcomplete buried forms.

The electric compressor with an integral inverter having theresin-charging structure according to the present invention isspecifically suitable for a compressor used in an air conditioningsystem for vehicles which strongly requires the reduction in cost andweight as a whole compressor.

EFFECT ACCORDING TO THE INVENTION

In the electric compressor with an integral inverter according to thepresent invention, because the resin is charged at an assembly-completedstate into the space to be charged with the resin which is defined bythe jig located in the receiving space, the resin coating can beperformed only at the essential site with the minimum resin usage, sothat the whole compressor can be reduced in cost and weight by the muchless amount of the charged resin and the resin usage.

BRIEF EXPLANATION OF THE DRAWINGS

FIG. 1 is a schematic vertical sectional view of the electric compressorwith an integral inverter according to an embodiment of this invention.

EXPLANATION OF SYMBOLS

-   1: electric compressor with integral inverter-   2: compression mechanism-   3: fixed scroll-   4: movable scroll-   5: ball coupling-   6: compressor housing (center housing)-   7: motor-   8: main shaft-   9: eccentric pin-   10: eccentric bush-   11: suction port-   12: compressor housing (front housing)-   13: discharge pore-   14: discharges chamber-   15: compressor housing (rear housing)-   16: discharge port-   20: receiving space-   21: motor drive circuit-   22: partition wall-   23: seal terminal-   24: lead wire-   25: IPM-   26: control circuit-   27: capacitor-   28: connector-   29: lid member-   31: jig-   32: space to be charged with resin-   33: charged resin-   34: drained resin-   35, 36, 37: site

THE BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, desirable embodiments of the present invention will beexplained referring to figures.

FIG. 1 shows electric compressor with an integral inverter 1 accordingto an embodiment of the present invention, and specifically shows anexample of the present invention applying to a scroll type electriccompressor. In FIG. 1, symbol 2 shows a compression mechanism consistingof fixed scroll 3 and movable scroll 4. Movable scroll 4 is swung tofixed scroll 3 in a condition that a rotation is prevented through ballcoupling 5. Motor 7 is incorporated in compressor housing 6 (centerhousing) and rotates main shaft 8 (rotation axis). Rotational movementof main shaft 8 is transformed to an orbital movement of movable scroll4, through eccentric pin 9 provided at one end of main shaft 8 andeccentric bush 10 which is engaged rotatably with it. In thisembodiment, suction port 11 sucking a refrigerant as a fluid to becompressed is provided in compressor housing 12 (front housing), and thesucked refrigerant is led to compression mechanism 2 through a sectionplacing motor 7, and the refrigerant which has been compressed bycompression mechanism 2 is delivered to an external circuit throughdischarge pore 13, discharge chamber 14, and discharge port 16 which isprovided in compressor housing 15 (rear housing).

Receiving space 20 is formed being circumscribed by an extended sectionof compressor housing 12 (front housing) and motor drive circuit 21 isprovided in receiving space 20. Specifically, motor drive circuit 21 isprovided at the exterior side of partition wall 22 which is formed incompressor housing 12 separating from the side of the refrigerantsuction path. Motor drive circuit 21 supplies electric power to motor 7via lead wire 24, and via seal terminal 23 (output terminal of motordrive circuit 21) attached by penetrating through partition wall 22, andthe side of refrigerant suction path and the side of a section placingmotor drive circuit 21 are sealed at a section placing seal terminal 23.By providing motor drive circuit 21 at an exterior side of partitionwall 22, at least some of electric parts including motor drive circuit21 can exchange heat through partition wall 22 with suction refrigerant,so as to be cooled by suction refrigerant.

Motor drive circuit 21 includes IPM 25 (Intelligent Power Module) whichcan perform an inverter function and control circuit 26, and electricparts such as capacitor 27, etc. are provided with it separately orintegrally. Motor drive circuit 21 is connected to an external powersupply (not shown) through connector 28 as an input terminal. Theopening side toward the outside of compressor housing 12 where electricparts including motor drive circuit 21 are mounted is covered in a statesealed with lid member 29, and these electric parts are protected by lidmember 29.

Electric parts such as motor drive circuit 21 and capacitor 27, etc. iscoated with a thermosetting resin, such as urethane or epoxy at apredetermined thickness (for example, 0.1 mm or more thickness), whichis charged at an assembly-completed state. This resin is charged with asfollows.

Jig 31 which has been preformed in a predetermined shape and used at thetime of the resin charging is inserted into receiving space 20 in acondition where lid member 29 is dismounted, so that space to be chargedwith resin 32 is defined by jig 31 located at a predetermined position.Space to be charged with resin 32 is defined as having a predeterminedvoid responding to a thickness of the charged resin, at the mountedelectric parts, etc. For example, after resin 33 is charged (forexample, poured with the liquid resin) from one side so as to fill inspace to be charged with resin 32, surplus resin 34 is drained from theother side and after the resin hardened, the charged resin is defined ina shape which responds substantively to the shape of space to be chargedwith resin 32. Therefore, the amount of the charged resin and resinusage can be greatly reduced in comparison with a charging wholly intoreceiving space 20.

In addition, jig 31 does not define space to be charged with resin 32 ata site which does not need to be charged with the resin, for example, atleast a part on an internal surface of compressor housing 12 definingreceiving space 20, such as site 35. Therefore, the resin is not chargedwith at site 35, therefore the amount of the charged resin and resinusage can be much more reduced.

Further, it is possible for jig 31 to define space to be charged withresin 32 for at least some of electric parts including motor drivecircuit 21, and for at least the other parts not define space to becharged with resin 32. For example, as shown in the FIGURE, a void(namely, space to be charged with resin 32) is formed betweenpredetermined site 36 and a mounted electric part (electric part with ahead section which does not need to be coated with the resin), so thatjig 32 is located substantively in contact with the electric part. Asdescribed above, space to be charged with resin 32 is not definedlocally at a site which does not need to be coated with the resin, so asto make the resin charging substantively unnecessary at the site,therefore the amount of the charged resin and resin usage can be muchmore reduced and the resin amount can be minimized. Such a reduction ofthe resin amount can achieve a reduction in weight and cost as a wholecompressor.

Further, in a region where distances among the mounted electric parts,such as site 37 shown in the FIGURE, are short and therefore theelectric parts are close to each other, space to be charged with resin32 can be formed as extending among the electric parts and therefore theintegral resin-charging straddling the electric parts can be performed.In this embodiment, because the electric parts close to each other areto be fixed to an integral charged resin section whose thickness is notlarge as is, each electric part can be kept in a desirable predeterminedform without damage to an electric connection, etc.

After the resin-charging is completed, lid member 29 can be mounted.Further, the electric parts, etc. can be also charged with the resinunder a residual heat condition after preheating as described above, orjig 31 itself can be controlled to be heated. Such configuration canmake the resin material fluidized better responding to the residualheat, so as to charge with the resin sufficiently even into a minimalspace in space to be charged with resin 32.

INDUSTRIAL APPLICATIONS OF THE INVENTION

The coating structure according to the present invention can be appliedto a general compressor with an integral inverter, and is specificallysuitable to a compressor used in an air conditioning system for vehicleswhich strongly requires lightweight and cost reduction as a wholecompressor.

1. An electric compressor with an integral inverter, incorporated with amotor and provided in a receiving space surrounded by a compressorhousing with a motor drive circuit that includes said inverter,characterized in that at least some of electric parts including saidmotor drive circuit are coated at an assembly-completed state with aresin that is charged into said receiving space, and a shape of saidcharged resin is defined in said receiving space by a jig used at thetime of resin charging and defining a space to be charged with saidresin.
 2. The electric compressor with an integral inverter according toclaim 1, wherein said jig defines said space to be charged with saidresin for said at least some of electric parts including said motordrive circuit and does not define said space to be charged with saidresin for at least a part of said compressor housing which defines saidreceiving space.
 3. The electric compressor with an integral inverteraccording to claim 1, wherein said jig defines said space to be chargedwith said resin for said at least some of electric parts including saidmotor drive circuit and does not define said space to be charged withsaid resin for at least the other parts.
 4. The electric compressor withan integral inverter according to claim 1, wherein said space to becharged with said resin is defined so as to extend between at least someof electric parts.
 5. The electric compressor with an integral inverteraccording to claim 1, wherein said at least some of electric partsincluding said motor drive circuit are provided in said receiving spaceso as to enable heat exchange with refrigerant sucked as fluid to becompressed.
 6. The electric compressor with an integral inverteraccording to claim 1, wherein charging of said resin is performed bycharging a liquid resin material into said space to be charged with saidresin.
 7. The electric compressor with an integral inverter according toclaim 1, wherein said at least some of electric parts including saidmotor drive circuit is charged with said resin under a residual heatcondition after heating.
 8. The electric compressor with an integralinverter according to claim 1, wherein said jig itself is formed so asto be heatable.
 9. The electric compressor with an integral inverteraccording to claim 1, wherein said resin material is a thermosettingresin.
 10. The electric compressor with an integral inverter accordingto claim 1, wherein a thickness of said charged resin is 1 mm or more.11. The electric compressor with an integral inverter according to claim1, wherein said compressor is a compressor used in an air conditioningsystem for vehicles.